Railway-traffic-controlling apparatus



Sept. 1, 1925. 1,552,144

L. O. GRONDAHL RAILWAY TRAFFIC CONTROLLING APPARATUS Original Filed Dec. 6, 1921 MQW INVENTORI BY a #w ATTORNEY Patented Sept. 1, 1925.

UNITED STATES PATENT OFFICE.

LABS O. GRONDAHL, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

RAILWAY-TRAFFIC-CONTROLLING ArrAaA'rus.

Application filed December 6, 1921, Serial No. 520,235. Renewed January 30,1925.

To all whom it may concern:

I Be it known thatL-Lans O. GRONDAHL, a citizen of the United States, residing at Pittsbur h, in the county of Allegheny and.

State of lennsylvania, have inventedcertain new and useful Improvements in Railway- Traflic-Controlling Apparatus, of which the following is a specification.

My invention relates to electrically operated signaling devices, such for example as electric lamps, and has for an object the provision of means for indicating at a distant point whether or not the device is operating in response to the supply. of electric current thereto. k

Broadly stated, I accomplish this object by means of a substance exposed to the heating effect of the current supplied to the signaling device and having a characteristic of varying in electrical resistance in response to variations in temperature. The indicat-- ing means is controlled by a circuit which includes such thermo-sensitive substance and a. source of current. I

Apparatus embodying my invention is capable of general application, and as an example it is well adapted for accomplishing the desired return indlcation when light signals are used in interlocking systems for railways, that is, switches and signals are controlled from a central point by an interlocking machine.

In connection with interlocking apparatus it is well understood that means must be provided for locking each signal lever in a preliminary or indicating position while moving from proceed position toward the stop position, and for releasing the lever only when the signal controlled thereby has assumed the stop aspect in response to the partial or preliminary movement of the lever. Vhen signals of the light type are employed, each signal usually'comprises at least two electric lamps, which indicate'stop and'proceed, respectively, when lighted, the circuits for the lamps being controlled by contacts actuated by the signal lever. It follows that means should be provided for releasingthe lever'only when the stop lamp is lighted.

en my invention is applied to appara tus of this character I provide means for releasing the lever from the indicating position when current is flowing in the lamp circuit but not at other times.

from the secondary 2 0 systems wherein agroup of a diagrammatic view showingone form of apparatus embodying my invention, and Figs. .2 and 3 are views showing modificaiions of parts of the apparatus shown in Similar reference characters refer to similar parts in each of the several views.

Beferrin first to Fig. 1, the reference character 5 designates a signal comprising two electric lamps G and R, which lamps when lighted are adapted to indicate Proceed and Stop, res ectively. lamps are at times sup ied with current and the supply of such current is controlled by a manually operable lever A. The primary 6 of transformer T is constantly supplied with alternating current from a suitable source which 1s not shown in the drawing.

G The supply of current to the signal lamps is attached to lever A and which'engages with a contact 5 or with a contact 5, according to the position of the lever. As shown in the drawing, the lever A is in the right-hand extreme position wherein contact 4.-5 is closed, so that lamp G is supplied with current through a circuit which passes from the right-hand terminal of transformer secondary 2 through wires 7 and 7", contact 4-5 wire 8, lamp G, and wires 9, 10 and 11 to the left-hand terminal of transformer secondary 2. When the lever A is shifted to the left, the is extinguished owing to the opening of contact 45, and the stop lamp R becomes lighted by virtue of a circuit which passes These and R is controlled by a contact 4 which.

a transformer T,

proceedlamp G may be completed.

i or indication device B should be prevented until an indication is received at the lever that the stop lamp R has become lighted. To accomplish this, the lever is provided with a lock or indication device B comprising a shoulder 15 on the lever, a dog 14 normally in position to engage with this shoulder, and a magnet coil 16 arranged when energized tov lift the dog 14 out of the path of the shoulder 15 by picking up an armature 16*. The parts are so proportioned that when the lever is shifted to the left, the shoulder 15 engages the dog 14 after contact 45 is closed, and that this contact remains closed after the movement of the lever has been completed.

The magnet coil 16 of the lever lock B is controlled by a thermo-sensitive element D which is exposed to the heat emitted by the heating element E. The element D has the characteristic of decreasing in electrical resistance in response to increase of temperature, and may conveniently be made of cupric oxide or' cuprous oxide.

The thermo-sensitive element D is coniiected in series with the magnet coil 16 and the secondary 2 of transformer T, the circuit being from the right-hand terminal of this transformer, through wires 7, 19.

and 19, magnet coil 16, wire 18, thermosensitive element D, and wires 13, 10 and 11 to secondary 2. The parts of this circuit are so proportioned and adjusted that when the lamp R is extinguished, so that the resistance of the thermo-sensitive element D is comparatively high, the current supplied to magnet coil 16 is not sufficient to lift the dog 14 out'of. the path of shoulder 15. When lamp R becomes lighted, however, so that the heating element E becomes hot and-the'temperature of the thermo-sensitive element D is increased, the resistance of element D is decreased and the current which is then supplied to magnet coil 16 is suflicient to lift the dog 14, so-

that the movement of lever A to the left desirable that the look ,It is, of course,

shall respond to the lighting of lamp R with as little delay as possible, and for this reason it may be advisable to keep the heating element E at a comparatively high temperature while lamp G is lighted so that only a comparatively slight rise in the temperature of this element is necessary to operate lock B when lamp R becomes lighted. This may be accomplished by connectin the upper end of element E with wire-8 y a resistance 25, as shown, so that while lamp G is lighted part of the current from transformer T- passes through this resistance and the heating element E, such current being sufficient to maintain E at a comparatively high temperature but not sufiicient to cause operation of lock B. The current thus shunted from lamp G must,.of course, not be sufficient to interfere with the proper lighting of this lamp.

If desired, a visual indicator may be provided at the lever A to show the operator whether the lamp G or the'lamp R of signal S is illuminated. This indicator, as here shown, comprises two incandescent lamps G and R, which are supplied with current from the transformer secondary 2 through a contact 21 which is operated by the armature16 When signal lamp G is illuminated, contact 21 is in its lowest position, so that indicator lamp G is lighted through a circuit which will be obvious from the drawing. When signal lamp R becomes lighted, the consequent elevation of the armature 16 shifts contact 21 to its upper position wherein the indicator lamp It becomes lighted through a circuit which willv likewise be obvious from the drawing.-

Referring now to Fig. 2, I have herein shown a modification of the apparatus shown in Fig. 1, in that the thermo-sensitive element D is subjected directly to the heat emitted by the filament 26 of lamp R. The lock magnet 16 is controlled by this element D in the same manner as in Fig. 1.

In Fig. 2 it will be noted that the thermosensitive element D is located outside of the bulb of lamp B. As an alternative, the structure shown in Fig. 3 may be used, wherein the filament 26 and 'the element D are both located inside of the lamp bulb 27, the lamp structure as a whole being designated It in this View. As with the modification shown in Fig. 2, the element D may be used to control the lock magnet 16 in the same manner as in Fig. 1. Although I have herein shown and described only three forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

-Having thus described my invention, what I claim is: A

1. In combination, a railway signalcomprising an electric lamp, a lever of an interlocking machine, means responsive to a partial movement of said lever for supplying lighting current to said lamp, a lock for preventing completion of the movement of said lever, a heating element associated with the circuit for said lamp, and means responsive to the heat emitted by said element for re-. leasing said lock.

2. In combination, a railway signal comprising an electric lamp, a lever of an in- 1 of said lever, a heating element associated with the circuit for said lamp, an element,

exposed to the heat emitted b said element and having the characteristic bf'varying' in electrical resistance in response to variations in'temperature, and means controlled by said thermo-sensitive element for releasing said lock when the lamp is lighted.

3. In combination, a railway signal comprising an electric lamp, a lever of an interlocking machine, means responsive to a partial movement of said lever for supplying lighting current to said lamp, a lock for preventing completion of the movement of said lever, a heating element associated with the circuit for said lamp, a thermo-sensitive element exposed to variations in the temperature of said heating element, and a circuit including said thermo-sensitive element and a source of current for controlling said lock,

4.-Incombination, a railway signal comprising an electric lamp, a lever of an interlockingmachine, means responsive to a partial movement of said lever for supplying lighting current to said lamp, a lock for preventing completion of the movement of said lever, a heating element associated with the circuit for said lamp, a thermo-sensitive element exposed to variations in the temperature of said heating element, a magnet for releasing said lock, and a circuit for said magnet including said thermo-sensitive ele- .ment and a source of current.

5. In combination, a railway signal comprising an electric lamp, an interlocking machine lever, means responsive to a partial movement of said lever for supplying lighting'current to said lamp, a lock for preventing completion of the movement of said lever, and means responsive to the heating effect of current supplied to said lamp for releasing said loc 6. In combination, a railway signal comprising an electric lamp, an interlocking machine lever, means responsive to a partial movement of said lever ing current to said lamp, a lock for preventing completion of the movement of said lever, and an element subjected to the heating effect of current supplied to said lamp and having the characteristic of varying in electrical resistance in response to variations in temperature, and means controlled by said element for releasing said look when the lamp is lighted.

7. In combination, a railway signal comprising an electric lamp, an interlocking ma- .chine lever, means responsive to a partial movement of said lever for supplyinglighting current to said lamp, a lock for preventing completion of the movement of said lever. a thermo-sensitive element exposed to the heating effect of current supplied to said lamp, and a circuit including said thermo-sensitive element and a source of currentfor controlling said lock.

trolling the supply of current to for supplying light- 8. In combination, a railway signal com-' prising an electric lamp, an interlocking machine lever, means responsive to a partial movement of said lever for supplying lighting current to said lamp, a lock for preventing completion of the movement of said lever, a magnet for releasing said lock, an element responsive to the heating eifect of current supplied to said lamp, and'means governed by said element for supplying current' to said magnet.

' 9. In combination, a railway signal comprising an electric lamp, a lever for consaid lamp,

a heating element associated with the circuit for said lamp, and means responsive to the heat emitted by said element when the lamp is lighted for controlling said lever.

10. In combination, a railway signal comprising an electric lamp, a lever for controlling the supply of currentto said lamp, a lock for governing said lever, a heating element associated with the circuit for said lamp, and means responsive to the heat emitted by said element when the lamp is lighted for releasing said-lock.

11. In combination, a railway signal comprising an electric lamp, a lever for controlling thesupply of current to said lamp, a heating element included in the circuit for said lamp, a thermo-sensitive element responsive to variations in the temperature of said heating element, and a circuit includrent supplied to said lamp for controlling said lock.

14. In combination, a signal comprising an electric lamp, a. heating element associated with the circuit for said lamp, an indicating device, and means responsive to the heat emitted by is lighted for controlling said device.

15. In combination, a signal comprising an electric lamp, a heating element assosaid element when the lamp ciated with the circuit for said lamp, a

thermo-sensitive element associated with said heating element and having one value of electrical resistance when the lamp islighted and another value of electrical resistance when the lamp is extinguished, and indicating means controlled by the resistance of said thermo-sensit-ive element.

16. In combination, a signal comprising an electric lamp, a heating element associated with the circuit for said lamp, and means for indicating at a remote point that said lamp is lightedvcomprising an element responsive to heat emitted by said heating element.

17. In combination, a signal comprising an electric lamp, a heating element associated with the circuit for said lamp, and means for indicating at a remote point that said lamp is lighted comprising a thermosensitive element exposed to the heat emitted by said heating element and having the characteristic of varying in electrical resistance in response to variations in temperature.

18. In combination, a signal comprising a lamp, a thermo-sensitive element, indicating means controlled by said element, and means associated with said lamp for suplying heat tosaid element when the lamp 1s lighted.

19. In combination, a signal comprising an electric lamp, a thermo-sensitive element subjected to the heating effect of current supplied to said lamp, and indicating means controlled by said element.

20. In combination, a signal comprising an electric lamp and indicating means for said lamp comprismg an element subjected to the heating effect of current supplied to said lamp and having the characteristic of varying in electrical resistance in response to variations in temperature.

21. In combination, an electrically operated device, and indicating means for said device-comprising an element subjected to the heating effect of current supplied to said device and having the characteristic of varying in electrical resistance in response to variations in temperature.

22. In combination, a signal comprising an electric lamp, and means for indicating at a remote point that said lamp is lighted, comprising a thermo-sensitive element exposed to the heating effect of current supplied to said lamp.

23. In combination, a railway signal comprising a proceed lamp and a stop lamp, an interlocking machine lever having proceed and stop positions, means controlled by said lever when in proceed position for supplying current to said proceed lamp and means responsive to a partial movement of said lever tothe stop position for supplying lighting current to said stop lamp, a lock for preventing complete movement of said lever to stop position, a heating element associated with the circuit for said stop lamp, a thermo-sensitive element, exposed to the heat emitted by said heating element, means controlled by said thermo-sensitive element and responsive to lighting current in the stop lamp circuit for releasing said lock.

and means operating when said proceed lamp is lighted to supply heat to said thermo-sensitive element but'not sufficient to cause release of said lock.

24. In combination, a railway signal comprising a proceed and a stop lamp, an interlocking machine lever, means controlled by said lever for supplying operating current to said proceed or said stop lamp according as the lever is in reverse or normal position, a lock for preventing movement of said lever to full normal position, a heating element associated with the circuit for said stop lamp, means including a thermo-sensitive element controlled by said heating element and responding to the normal operating current in said stop. lamp circuit to release said lock, and means operating when said proceed lamp is energized to supply to said heating element a substantial amount of current but not suiiicient tocause release of said lock.

25. In combination, a railway signal comprising a proceed lamp and a stop lamp, an interlocking machine lever having proceed and stop positions, means controlled by said lever when in proceed position for supplying current to said' proceed lamp and means responsive'to a partialmovement of said lever .to the stop position for supplying lighting current to said stop lamp, a lock for preventing complete movement of said" lever to stop position, a heating element associated with the circuit for said stop lamp, a thermo-sensitive element exposed to the heat emitted by said heating element, means 1 cont-rolled by said 'thermo-sensitive element and responsive to lighting current in the stop lamp circuit for releasing said lock, and 'means operating when said proceed lamp is lighted for supplying a substantial amount of current to said heating element but not enough. to cause release of said lock.

26. In combination, a railway signal com-. prising an electric lamp, a lever for controlling the supply of current to said lamp, 1 a lock for governing a movement of said lever, a heating element associated with the circuit for said lamp, means responsive to the heat emitted by said element when the lamp is lighted for releasing said lock. and means operating when said lamp is not lighted to supply current to said heatingele ment but not sufficient to cause release of said lock.

27. In combination, a signal comprising an 7 vice including a thermo-sensitive element lighting current to said lamp, a lock for subjected to the heating efi'ect of current preventing completion of the movement of supplied to said device, and means operating said lever, a heating element associated when said device is de-ene-rgized for sup- WVith the circuit for said lamp, means re- 15 5 plying heat to said element but not enough sp nslve to he heat emltted by said eleto cause operation of said indicating ment'for releaslng said lock, and means means. for supply ng heat to sa1d e1ement wh en 29. In combination, a railway signal com- Sald p Is not hghted but In q y prising an electric lamp, alever of'an int sufiicient to cause release of said lock. 20

' locking machine, means responsive to a par- In testimony whereof I y Signaturetial movement of said lever for supplying LARS O. GRONDAHL. 

